Expulsion-fuse cut-out



July 29, 1930. I. SJ RAYMER EXPULSION FUSE CUT-OUT Filed Feb. 4, 1925 2Sheets-Sheet 2 4 ATTORNEY Patented July 29, 1930 IRA s. RAYMEJK, orBEAVER, PENNSYLVANIA nxPULsIoN-rUsn CUT-OUT Application filed February4, 1925. Serial No. 6,796. g

This invention relates to expulsion fuse cut-outs and more part1cularlyto fuse cutouts for use in connection with high-tensioncircuits atexposed locations. In connecting transformers or other electricalequipment to high-tension transmission lines or other high voltagesources, it is desirable to provide a cut-out or circuit breakin meanswhich will break the circuit upon an excessive flow of current and will.

open up a long gap atsuch break so as to ex tinguish the are whichfollows the interruption of a high voltage circuit.

\Viththe above and other considerations in is mind, it is an object ofthe present invention to provide a cut-out device of the expulsion fusetype, which. utilizes an explosive com.- pound ignited by an excessiveflow of current and acting to rupture the circuit, to extin 2e guish thearc and to releasespring means or the like which act to open up and'tomaintain a wide gap in the circuit. It is another object of for use onpoles or other elevated or remote structures which will give such an.indica tion of the condition of the fuse by the rela live position ofits parts as will enable the operator to easily ascertain from a int onto the ground whether or not the fuse as been blown.

It is a further object of this invention to provide an expulsion fusecut-out which may be used as a quick-acting disconnecting 3.) switch.

It is a still further object of this invention to provide a fuse cut-outhaving a cheap and compact replacement unit which may be readily removedand inserted.

It is another object of this invention to provide a combined expulsionfuse, disconnecting switch and reactance coil in a single compact unit.I

It is another object of this invention to provide an, expulsion fusestructure including a sealed chamber for housing a fuse wire andprotecting it against injury.

Other objects and advantageous features of the present invention willbecome apparcut as the description thereof progresses.

this invention to provide an expulsion fuse cut-out suitable In thedrawings, Fig. 1 represents a side elevation of the expulsion fusecut-out comprising the presentinvention, together with one form ofmounting therefor;v

Fig. 2 is a sectional end view of the spring fuse clips taken along thesection line 22 of Fig.1;, g

' Fig. 3 isa fragmentary sectional to view of the contact structuretaken along t e section line 3-3 of Fig. 1; I I i I Fig. 4 is aperspective View of a portionof oneof the fuse carrying bars; A

F ig. 5 is a side elevation of a modified form of a fusecut-outcomprising a combined fuse, disconnecting switch and choke coil,together witha mounting therefor; i 1

Fig. 6 is an end view of the structure shown in'Fig.5; I, i

Fig. 7 is a sectional view of a portion of the fuse carrying structure,taken along the line 7r-7 of Fig. 6 and viewed in the direction of thearrows; Fig. 8 is a side elevation of the fuse carrying structure on anenlarged scale; and

Fig. 9 is a sectional View of the structure shown in Fig. 8, taken alongthe line 9-9 and viewed in the direction of the arrows. Referring toFig. 1, the fuse structure is supported on two insulators 1 and 2, ofthe well known petticoat pin type, which are carried by a U-shapedsupporting bar 3, these insulators beingcomposed of porcelain, glass, orany other suitablematerial. As the structures carried by theseinsulators 1 and 2, are substantiallyidentical, a detailed descriptionof the apparatus carried on one of them, only will be given, thecorresponding parts carried by the other insulator being designated bylike reference characters. The ,bar 3 may be secured to any suitablysupported structure, such as the bracket or rod 4,, by means of thebolts 5 and 6. .A circular metallic cap .7, is cemented over the upperportion of the insulator 1. This cap is provided with .a vertical lug orplate 9 which is preferably made integral'with the cap and extendsdiametrically across its upper surface as shown.

1 Fuse holding clips are secured to the lug 9 by means of the bolts 11.These clips in the specific form shown consist of three verticallyarranged clip members 12, 13 and 14, which are preferably stamped fromresilient sheet copper. The clip members 12, 13 and 14 are flaredoutwardly at their upper ends as shown at 15 and 16 in Fig. 2, in orderto facilitate the insertion of the fuse blades. The clip member 12 isprovided with an in wardly extending catch or hook 17. which is formedby bending a portion of the clip near its upper edge at right angles tothe body of the clip as clearly shown in Fig. 3, the edge of this catchbeing beveled as shown in Fig. 2, so that said catch tapers in width.

The lug 9 also carries a fuse separating or expulsion spring 18 whichacts to throw the fuse end as hereinafter described. This spring 18 ismade of heavy spring steel wire in the form of a loop 19 which passesaround the fuse holding clips 12-, 13 and 14 as shown in Figs. 1 and 3;the ends of the loop being formed into coiled springs 20 carried on thepin 21, which passes through the lug 9. A U-shaped retaining clip 22 iscarried on the pin 21 as shown, and serves as a stop for the ends of thecoiled spring 20.

The fuse structure proper consists of two members which are adapted tobe widely separated when the fuse acts to open the circuit. Each memberconsists of a metallic end piece E and a fuse carrying bar 24. The endpieces are composed of copper'or some other suitable conducting materialand are provided with blades 25 which are adapted to be firmly retainedby the clip members 12, 13 and 14, as

shown. Each blade 25 is provided with an opening 26 to facilitate theremoval of the fuse structure, as hereinafter described. A small notch42 is provided in the upper edge of the blades 25 and cooperates withthe catch 17 to prevent the blades from being forced out of the clips12, 13 and 14 when the fuse is blown. A fiat strip 27, integral witheach end piece E, extends upwardly at one end of each fuse blade 25, andis bent back in a horizontal plane over the blade and the clips 12, 13and 14 as shown. These strips '27 act as stops, as hereinafterdescribed, and also act as shields to prevent the entrance of dirt orother foreign matter between the clips. Each end piece is provided withtwo downwardly extending legs 28 and 29 which are connected by a rod 30,against which the loop 19 of the spring 18 is arranged to hear when thefuse structure is in place. Each fuse carrying bar 24 is clamped to anend piece E by means of an angle piece 32 and screws 33, the angle piece32 being secured to the end piece by means of the rivets 34. The fusecarrying bars 24 are composed of any suitable insulating material,preferably of a frangible and moisture-proof naturesuch as a phenoliccondensation product. A small cup-like depression or cut out portion 35is provided near the free end of each of the bars 24, and a groove 8 isprovided leading from this depresion to the other end of the bar asclearly shown in Fig. 4.

Suitable fuse wires 36 (see Fig. 4) are carried in the grooves 8, thesegrooves being subsequently filled with a suitable moisture proofinsulating cement. The fuse Wires 36 are so constructed as to have apoint of initial fusibility directly over the depressions 35 in the bars24. This feature may be accomplished by using copper wire in the grooves8 and a fusible wire across the depressions 35, or any other suitablemeans may be provided to accomplish this result. In the specificembodiment shown, a double fuse wire is provided in the grooves 8 and asingle fuse wire is used at a point directly over the depre sions 35.The bars 24 overlap at their free ends in such a manner that thedepressions 35 coincide to form a closed chamber. 'hen the fusestructure is assembled, the depression's 35 are filled with an explosivesubstance such as gun powder which will ignite and explode withconsiderable force at a suitable temperature. The engaging surface ofthe plates 24 are covered with a suitable moisture-proof insulatingcement and are clamped or pressed together until the cementing substancehas hardened. From the above description, it is clear that the explosivesubstance in the chamber together with the fuse wires is carried in amoisture-proof enclosure and is so suitably protected for use at pointsexposed to the weather.

A choke coil is preferably provided in connection with the fuse toprotect it against surges of current due to lightning or other causes.This coil may be of any suitable construction, but in the embodimentshown consists of a vertically arranged plate 37 of insulating materialcarrying a coil 38 of heavy wire, preferably copper, which is woundthrough rows of holes 39 and 40, in the plate 37. The choke coil issecured to the lug 9 by means of an angle bar 41 of conducting material,to which one terminal of the coil electrically connected as clearlyshown.

As pointed out above, the portion of the fuse wire 36 which extendsthrough the depression 35 is of such a composition and cross sectionthat an excessive amount of current heats it to a temperature at whichit melts and separates. As the fuse wire separates and opens thecircuit, an arc is drawn which ignites the explosive substance containedin the'chamber, and as this explosive is closely confined, it willexplode with considerable violence, rupturing the bars 24. This ruptureof the bars ordinarily occurs at the depressions 35 where the crosssection of the bars is reduced and where the force of the explosion isgreatest. If desired, the explosive substance may be made to ignite attemperatures below the melting point of the fuse, thus utilizing theforce of the explosion to break the circuit. When ruptured by theexplosion, the ends of the bars 24 together with the end piecesEarethrown upwardly and apart by the springs 18, thus widely separatingthe ruptured ends of the fuse wires 36, and placing the bars 24 in sucha position that the condition of the fuse can be readily determined.This indication of the condition of the fuse is of considerableimportance as fuses of this type are ordinarily mounted on poles orother elevated structures and the marked change in the appearance ofthedevice when blown makes its condition readily apparent to the operatorfrom the ground or other remote point. As the blades are thrown upwardlyby the springs 18, the notches 42 in the blades strike the catches 17 onthe clips 12, and this engagement prevents the blades from being forcedout of the clips, and also acts as a fulcrum about which the blades areswung. As the blades 25 are swung upwardly, the ends of the strips 27come into engagement with the clips 22,'and so act as stops to limit themovement of the blades and their associated bars 24.

When the fuse cutout is designed for large currents, a heavy fuse wireis used, and in this case theexplosive substance may beomitted from thechamber, the arc and gases formed by the burning of the fuse wire beingsufiicient to rupture the blades and open the circuit. a

After the fuse has been blown, the blade members 25 have been acted onby springs 19 to rotate them substantially 90 to thus free the notches42 from the projections 17, and thus they may be removed by inserting ahook or other suitable tool through the openings above the rod-s anddrawingthe blades 25 outwardly from between theclips. The ends of theruptured bars 24, are now removed from the end pieces E, and areplacement unit, comprising two bars 24 cemented together and providedwith fuse wires being properly cleaned and clamped securely in contactwith the end pieces by means of the screws 33. The renewed fusestructure may now be inserted by forcing the blades 25 into the clipmembers and under the catch 17 It is sometimes found necessary to openthe circuit through the fuse in order to make replacements or repairs.This may be readily accomplished by inserting a hook or other toolthrough the opening 26 in one of the blades 25 and releasing thecorresponding catch 17. The springs 18 will thenthrow the released blade25 out of its clips 12, 13 and 14, and the released end of the fusestructure will be thrown outwardly, the other blade being retained inthe clips by its catch 17 and notch 42, and the movement of the fusestructure being limited by the engagement of the end of the strip 27with the clip 22. The fuse structure will be positively held in thisopen position by the spring18 so that it cannot be swung closed by windpressure or vibration. In this manner, it is clear that the fusestructure of the present invention also constitutes a ositive andquick-acting disconnecting switch or cut-out.

Referring now more particularly to Figs. 5 through 9, a modified form ofa fuse cutout has been shown. In this modification, the fuse structureis supported by two petticoat pin type insulators 44-and'45 which-aresecured to a suitable supporting bar 46 by the bolts 47. The insulators44 and carry two downwardly extending metallic legs 48 and 49respectively, the leg 48 carrying a conducting metallic plate 50, andthe leg 49 carrying a conducting plate 51, secured thereto by suitablebolts 52, as shown. A downwardly extending clip member 53, having abifurcated end, is secured tothe plate 5O by the screw 54, and carries ablade member 55, pivotally secured thereto by the bolt 56 as shown.

The switch blade portion of the modified cut-out includes a choke coil,constructed in the same manner as the choke coil shown in Fig. 1, havinga vertically arranged plate of insulating material 57 provided with twoparallel rows of holes 58 through which the wire 59 of the choke coil iswound. Blademembers and 60 arebol ted to either end of the insulatedplate 57, and are electrically connected to the opposite ends of thechoke coil by the connectors 61 and 62 respectively as shown. In orderto maintain a good electrical connection between the plate 50 and theblade 55, a flexible cable 63 is connected be-- tween thesemembers,forming a parallel electrical path around the pivotal connectionbetween the clip member 53 and the blade member 55. I l

The fuse structure in the modification shown in Figs. 5 through 9 issecured between the plate 51 and the blade 60. An inverted U-shapedmetallic member 64,11avinginwardly projecting edges 65'. is secured totheplate 51 by the screw bolts 66.,the heads of these bolts beingcountersunk in the member 64 as in its lower face as most clearly shownin Figs. a

8 and 9. The ends of theblock 67 are tapered and rounded as shown, andare provided with vertically extending holes, 87. i A lower block 69 ofinsulating materiahhaving a reduced upper portion, is secured to thelower face of the block 67 by means of a suitable cement or glue,preferably of a waterproof nature, and covers the depression 68 in theblock 67, forming a closed chamber between the two blocks. The block69is provided with two metallic contact plates 7 O, securedto oppositesides of the reduced upper portionthereof by the rivets 71, these plates70 being adapted to engage depressions 72 in the in-turnededges 65 ofthe member 64 when the block67 is held in the member 64 as shown inFigs. 5 and 6. A metallic plate 73 and switch blade clips 7 4 aresecured to the lower face of the block 69 by the bolts 75 and 76. Asclearly shown in Fig. 9, the bolt 75 is entirely enclosed by the block69 while the bolt 76 passes through to the upper face thereof and isprovided with a terminal screw 77 in its upper end, this terminal screwlying within the depression 68 when the blocks 69 and 67 are cementedtogether. A second terminal screw 78 is provided in the upper face ofthe block 69, and engages one of the rivets 71 connected to the contactplates 70. A fuse wire 79 is connected between the terminal screws 77and 78 when the fuse structure is assembled, the depression 68 beingpreferably filled with an explosive substance and the blocks 69 and 67being then cemented together. It is clear that when the fuse structureis assembled, and the blade 60 engages the clips 74, the fuse wire 79 isincluded in an electrical circuit between the blade 60 and the plate 51,this circuit including the bolt 76, the screw 78, the rivet 71, theplates and the U-shaped member 64.

An extension 80 is provided on the plate 73 and has two downwardlyextending legs 81, provided with outwardly turned extremities 82 havingslots 83 therein as shown. The legs 81 are provided with openings whichcarry a spring retaining loop or latch 8st which is adapted to pass overthe end of the blade 60 and to retain this blade between the clips 7 4.The edges of the extremities 82 may be beveled or rounded to permit thelatch to be pulled outwardly to release the blade 60. A loop of springwire '85 is coiled about the ends of the bolt 56; its extreme endspassing over the blade member 55 and the clip member 53; and biasing theblade member to turn in a clockwise direction about the bolt 56 therebytending to separate the blocks 69 and 67 andto swing choke coilstructure downward when the fuse is blown. In certain cases, the spring85 may be omitted, the blocks 69 and 67 being separated by gravity whenthe fuse is blown.

The operation of the modification shown in Figs. 5 through 9 is similarto that of the modification shown in Figs. 1 through -i. Vhen anexcessive current flows, the fuse wire 79 melts and separates, ignitingthe explosive substance contained in the depression 68. rupturing thecement and blowing the blocks 67 and 69 violently apart. The spring 85acts to swing the block 69 together with the clips 74, the blade 60 and.the choke coil structure rapidly downward and away from the member 64,this entire structure being pivoted about the bolt 56 passing throughthe blade 55. As the blocks 67 and 69 are separated, the contact plates70 disengage the edges of the U-shaped member 64, thus breaking thecircuit if it has not already been broken by the burning of the fusewire. If the currents used are comparatively large, the explosivesubstance may be omitted, the gases formed by the burning of the fusewire being sufficient to separate the blocks 67 and 69. After the fusehas been blown and the circuitis again in condition to be closed, theblock 67 is pulled out of the member 6% by means of a hook or other toolinserted in one of the holes 87, and anew unit, comprising two blocks 67and 69, cemented together and provided with a fuse wire and theexplosive substance, and carrying the clips 74, is pressed into themember 64. This new fuse structure is held in the proper relation to theren'iainder of the structure by means of the engagement of the contactplates 70 with the depressions 72 in the edges of the member 64. Theblock 69 carrying the burned out fuse wire, together with the clips 74;and the latch 84 is removed from the blade 60, and the blade is thenswung up by means of a hook or other suitable tool inserted in theopening 86 of the blade 60, the latch 84 of the new fuse and clipstructure being dropped over the end of the blade 60 to hold it inplace. The spring 85 is sprung on to the extension 55, and the replacedfuse structure is then in condition for operation.

It is obvious that by swinging the latch 84. away from the blade 60 andinserting a hook or other tool in the opening 86 of the blade 60, thisblade, together with the choke coil structure, may be swung downward andout of engagement with the clips 74, thus opening the circuit throughthe device. In this manner, the device may be used as a disconnectingswitch.

It is seen that a structure has been provided which acts as a combindexpulsion fuse, a dis connecting switch and a choke coil, thearrangement being extremely simple and compact and the fuse unit beinginexpensive and readily replaced.

Vhen comparatively heavy currents are to be carried by the fusestructure, it is often desirable to invert the arrangement shown in Fig.5 mounting the combined choke coil, dis connecting switch andfusestructure above the insulators and securing the lower ends of theinsulator pins to a support. hen arranged in this manner, the are formedby the rupture of the circuit would be blown upward in a manner similarto the operation of the well known horn gap, and would be extinguishedwithout damaging the cut-out structure. In such an inverted arrangement,the spring 85 would have to be made strong enough to swing the entirechoke coil and fuse structure upward and the latch 84 would be providedwith some suitable spring retaining means. This is such an obviousn'iodification of the forms shown in the drawings, that specificillustration of the same is deemed unnecessary.

As the present invention has been disclosed and described in connectionwith a rather specific form of fuse structure, it should be clearlyunderstood that the invention is not limited in its scope I to thestructure shown, and that many changes and variations of structure mightbe made without departing from the spirit of the invention as defined bythe appended claims.

What it is desired to secure by Letters Patcut is '1. In a fuse cut-out,a wire having a fusible portion, a member having an enclosed chambersurrounding said fusible portion, said member comprising an element ofinsulating material having a receiving chamber therein, and an explosivesubstance Within said chamber to cause a rupture of said member and aseparation of said wire when said fusible portion reaches apredetermined temperature and elastic means for moving apart theseparated parts.

2. In an electric cut-out, acurrent carrying means, an explosivesubstance for separating said means at a predetermined temperature, andmechanical means for moving apart the separate parts of said element.

3. In combination, a choke coil, a disconnecting switch and an expulsionfuse suspended between two supports, said fuse acting on overload tomove said supports apart to thus separate conducting members and open acircuit.

4. In combination, a supporting structure comprising two supportscarrying c0nducting members, and means electrically connected betweensaid members including a choke coil and an expulsion fuse, said fusebeing adapted to move the supports apart to separate said conductingmembers.

5. In a fuse cut-out, an insulating support, a choke coil pivotallysecured to said support, a switch blade rigidly secured to said chokecoil, clip means for engaging said switch blade and a separableconnection for securing said clip means to a second insulating supportcomprising two members, one of insulating material, carrying a fuse Wiretherebetween.

6. In a fuse cutout, two insulating supports, a choke coil having oneend thereof electrically connected to and pivotally supported by one ofsaid supports, and means for separably connecting the other end of saidchoke coil to the other of said supports comprising two separablemembers, one of insulating material, carrying a fuse Wire and anexplosive substance therebetween.

7. In a fuse cut-out, a separable means for securing a switch blade to aterminal comprising, a first member of insulating material secured tosaid terminal and having a depression, a second member of insulatingmaterial connected to said first member, a fuse wire carried by saidmembers and lying in the depression in saidfirst block, blade retainingmeans secured to the exposed face of said second member and means forelectrically connecting said fuse wire in a circuit between said bladeretaining means and said terminal.

8. In a fuse cut-out, a switch structure comprising a choke coilconnected in series between two blades, a pivotal support for one ofsaid blades, a clip for retaining the other of said blades and a fusestructure for securing said clip to an insulating terminal platecomprising two separable blocks carryin g a fuse wire therebetween, anda normally tensioned spring acting to separate said blocks when saidfuse Wire is blown.

In testimony whereof I afiix my signature.

' IRA S. RAYMER.

